How to use Solar charge controller as Battery charger only

[bobby78]

I have this EPsolar Landstar LS1024B 10A solar charge controller which I want to use as float charger for my 120AH lead acid car battery , I don't have Solar panels therefore I need some DC power source to simulate Solar panels,
An immediate alternate can be my Del laptop charger which outputs 18.5V at 3Amp, I will directly connect its wire to Solar panel input of charge controller and theoretically it should work but due to my very limited electrical knowledge I don't know if I'm missing something in between

So is it OK to use this setup or this can damage my tiny charger since I need to charge a big battery? DO I need to add anything else between Laptop charger and charge controller?

My charge controller
epsolar-ls1024b-12v_24v-10-ampere-accu-laadregelaar-_245_1.jpg

[Mike90250]

you could smoke your laptop charger. The way PWM charge controllers work, is they load the battery right onto the power source. Connecting a 24V battery to the input of a 12v controller will blow the controllers internal fuse, as the battery dumps power into the 12v battery.
A small power supply is not likely to hurt the controller, but it may overheat or be damaged as it dumps power into the 12V battery. After the battery is full, and the controller cuts back the charge, it should be OK.

[jflorey2]

So is it OK to use this setup or this can damage my tiny charger since I need to charge a big battery?

Depends on the design of the laptop supply. It may overcurrent and blow a fuse, or it might go into a hard current limit and shut down. It might go into a soft current limit and just limit current; in that case it might work. However be aware that you will then be using it way over its rated current, and it may not last long.

If you want to do a float charge, just get a battery maintainer. They are cheap and easy to use.

[bobby78]

you could smoke your laptop charger. The way PWM charge controllers work, is they load the battery right onto the power source. Connecting a 24V battery to the input of a 12v controller will blow the controllers internal fuse, as the battery dumps power into the 12v battery.
A small power supply is not likely to hurt the controller, but it may overheat or be damaged as it dumps power into the 12V battery. After the battery is full, and the controller cuts back the charge, it should be OK.

Thankyou for clarifying by the way controller supports input upto 50V as per manual(but there is no mentioning of Current/amp),
So what should be the specs of Power Supply to simulate Solar panels to charge a battery this size ? Actually this Controller is user programmable and I want to use advantage of its 3 stage charging algorithm along with programmable parameters ..

Controllers Input Power input Spec
untitled.JPG

[bobby78]

Depends on the design of the laptop supply. It may overcurrent and blow a fuse, or it might go into a hard current limit and shut down. It might go into a soft current limit and just limit current; in that case it might work. However be aware that you will then be using it way over its rated current, and it may not last long.

If you want to do a float charge, just get a battery maintainer. They are cheap and easy to use.

Actually as I mentioned in comment above I want to take advantage of this controller's user programmable charging options and since I already have something in hand therefore I was trying to experiment even if I have to purchase some Good power source for it All I'm looking for is what kind of POwer source would be appropriate for this kind of application

Also can you please explain why would it over current?

[jflorey2]

Actually as I mentioned in comment above I want to take advantage of this controller's user programmable charging options . . .

OK then it's not a float charger.

and since I already have something in hand therefore I was trying to experiment even if I have to purchase some Good power source for it All I'm looking for is what kind of POwer source would be appropriate for this kind of application

The ideal would be a bench supply - a current and voltage limited supply that you can adjust, and that has current and voltage monitoring. That's designed to provide a limited amount of current at a certain voltage, which is what you want. Indeed the ability to limit both makes it look a lot like a solar panel to the PWM controller.

Second best would be a power supply that is designed as a battery charger, like the Batmod line of modules from Vicor. They require some integrating to get them to work.

Third best would be a power supply that does constant current limiting and has an adjustable output. For example, the MeanWell SE-350-15 can be adjusted downward and will do constant current limiting. The problem is that it's rated for 350 watts and will try to go to as high as 470 watts to charge the battery - which means that it will tend to overheat. In addition, the control loop will probably not appreciate seeing full load to zero load swings as the PWM controller does its thing. But it might work. I have used such supplies as battery chargers before, and they can work.

Also can you please explain why would it over current?

Because you will be connecting an 18 volt supply to a 12 volt battery. The supply will do its best to pull the battery up to 18 volts. It will fail. How it fails will determine what happens next. Best case is that it simply current limits. That can work, although current limit is almost always above what the supply is rated for for manufacturability reasons.